The number of young physicians choosing a career as a physician-scientist has declined dramatically over the last twenty years. To address this deficiency, an intense three-year laboratory-based training program, referred to as the Physician Scientist Research Training Program (PSRTP), was developed at the University of California, San Diego School of Medicine. The first class of trainees entered the PSRTP in June of 2000, and to date, 14 trainees have been accepted into the program, with an equal number being M.D.s, and M.D./Ph.D.s. The training program is specifically designed for physicians who have completed a general clinical residency, for example in internal medicine or pediatrics. There are no clinical obligations during the three-year training period with the trainees devoting themselves full time to laboratory work. By several criteria, the program has been highly successful with the first set of three trainees who entered in 2000 currently having appointments as Assistant Professors, and actively performing research. The present proposal requests continuation of the program with two training positions at each level for a total of six training slots. Sixteen faculty members, including one from the Salk Institute, will serve as research mentors with their research areas corresponding to those of the mission of the National Institute of Diabetes and Digestive and Kidney Diseases. Thus, the trainees will conduct research on projects relevant to the NIDDK, and based on the experience to date, it is anticipated that about half of the trainees will seek further clinical training, most likely in endocrinology, hematology, or nephrology. The other half of the trainees will likely embark directly on an investigative career